PROJECT SUMMARY Out-of-network care is 2-3 times more common in mental health care compared with general health care, with 18 percent of privately insured mental health care users using an out-of-network mental health provider in the past year. Yet, no research has considered why there are such large differences and their consequence. We propose to field a web-based nationally representative survey of individuals with private insurance who have used an out-of-network mental health provider or considered using an out-of-network mental health provider in the past year. In Aim 1 we will determine why individuals use or consider using out-of-network mental health care. Factors patient may consider include whether an in-network provider is available, preferences related to provider type, the benefits of maintaining a relationship with a current provider who is no longer in-network, privacy concerns, perceived provider quality as well as others. In Aim 2 we will determine the consequences of mental health provider networks for individuals with mental health disorders. Provider networks may affect access to care (including the decision whether to use any mental health services), continuity of care (changing providers), type of treatment (e.g. use of psychotherapy versus medication alone), and out-of-pocket costs (including balance billing). In Aim 3 we will investigate the implications of mental health provider networks for plan choice and selection into health plans. If patients actively consider whether a preferred mental health provider is in a plan's network before choosing a plan, plans may benefit from excluding providers who serve high-cost patients from their network. In addition to providing important new information on out-of-network service use in mental health, this study will be used to develop hypotheses for new research. We expect future studies derived from this work may include the use of administrative data to examine effect of plan network size and composition on quality and type of care received, particularly by individuals with SMI, and the use of data from State Health Insurance Marketplaces to evaluate whether and how the composition of mental health provider networks affects selection into plans. As plans continue to increase their use of provider networks to control costs, it is critical to understand the effects on access to care, quality of care and financial burden for individuals with mental health disorders. Better understanding the reasons for high out-of-network use in mental health care will help to determine which of the current policies being considered are most likely to lead individuals with mental health disorders to have similar access to care as individuals with general medical disorders.